class_uses
(PHP 5 >= 5.4.0, PHP 7, PHP 8)
class_uses — Return the traits used by the given class
说明
class_uses(object|string
$object_or_class, bool $autoload = true): array|false
This function returns an array with the names of the traits that the
given object_or_class uses. This does however not include
any traits used by a parent class.
参数
-
object_or_class -
An object (class instance) or a string (class name).
-
autoload -
Whether to call __autoload by default.
返回值
An array on success, or false when the given class doesn't exist.
范例
示例 #1 class_uses() example
<?php
trait foo { }
class bar {
use foo;
}
print_r(class_uses(new bar));
print_r(class_uses('bar'));
spl_autoload_register();
// use autoloading to load the 'not_loaded' class
print_r(class_uses('not_loaded', true));
?>
以上例程的输出类似于：
Array
(
[foo] => foo
)
Array
(
[foo] => foo
)
Array
(
[trait_of_not_loaded] => trait_of_not_loaded
)
add a note
User Contributed Notes 7 notes
stealz at op dot pl ¶
9 years ago
To get ALL traits including those used by parent classes and other traits, use this function:
<?php
function class_uses_deep($class, $autoload = true) {
$traits = [];
do {
$traits = array_merge(class_uses($class, $autoload), $traits);
} while($class = get_parent_class($class));
foreach ($traits as $trait => $same) {
$traits = array_merge(class_uses($trait, $autoload), $traits);
}
return array_unique($traits);
}
?>
Jos Macedo ¶
1 year ago
Another alternative to get all parent traits is:
<?php
function getUsedTraits($classInstance) {
$parentClasses = class_parents($classInstance);
$traits = class_uses($classInstance);
foreach ($parentClasses as $parentClass) {
$traits = array_merge($traits, class_uses($parentClass));
}
return $traits;
}
?>
donatj at gmail dot com ¶
1 year ago
The popular stealz solution doesn't handle traits that use other traits. A little bit of recursion can clean the entire thing up a bit and make it more robust.
<?php
public function class_uses_deep( string $class, bool $autoload = true ) : array {
$traits = class_uses($class, $autoload);
if($parent = get_parent_class($class)) {
$traits = array_merge($traits, class_uses_deep($parent, $autoload));
}
foreach( $traits as $trait ) {
$traits = array_merge($traits, class_uses_deep($trait, $autoload));
}
return $traits;
}
?>
ulf ¶
8 years ago
A slighly modified version from Stealz that also checks all the "parent" traits used by the traits:
<?php
public static function class_uses_deep($class, $autoload = true)
{
$traits = [];
// Get traits of all parent classes
do {
$traits = array_merge(class_uses($class, $autoload), $traits);
} while ($class = get_parent_class($class));
// Get traits of all parent traits
$traitsToSearch = $traits;
while (!empty($traitsToSearch)) {
$newTraits = class_uses(array_pop($traitsToSearch), $autoload);
$traits = array_merge($newTraits, $traits);
$traitsToSearch = array_merge($newTraits, $traitsToSearch);
};
foreach ($traits as $trait => $same) {
$traits = array_merge(class_uses($trait, $autoload), $traits);
}
return array_unique($traits);
}
?>
Daniel Klein ¶
4 years ago
If the class does not exist, you will get a warning, even if $autoload == false; I.e., if the class is not found, setting $autoload to false is not sufficient to silence the warning.
This is different from class_exists ($class_name, $autoload = true), which doesn't generate a warning in either case.
Daniel Klein ¶
4 years ago
I have improved on ulf's improvement of stealz' code. I'm pretty sure the last "foreach" adds nothing, so I've removed it, as well as adding a check for string class names (as opposed to objects) to prevent the warning if the class is not found:
<?php
function class_uses_deep($class, $autoload = true) {
$traits = [];
// Get all the traits of $class and its parent classes
do {
$class_name = is_object($class)? get_class($class): $class;
if (class_exists($class_name, $autoload)) {
$traits = array_merge(class_uses($class, $autoload), $traits);
}
} while ($class = get_parent_class($class));
// Get traits of all parent traits
$traits_to_search = $traits;
while (!empty($traits_to_search)) {
$new_traits = class_uses(array_pop($traits_to_search), $autoload);
$traits = array_merge($new_traits, $traits);
$traits_to_search = array_merge($new_traits, $traits_to_search);
};
return array_unique($traits);
}
adam at adamhahn dot com ¶
9 years ago
FYI: It is not explicitly stated, but if you run this function against a class that does not use any traits it will return an empty array.
<?php
class iDontUseTraits {
}
class_uses('iDontUseTraits'); // Returns empty array
?>